Diagonal impeller for a diagonal fan, and diagonal fan

ABSTRACT

A diagonal impeller for a diagonal fan ( 11 ), comprising a carrier plate ( 33 ) over the outer periphery of which a plurality of vanes ( 36 ) are distributed, wherein the vanes ( 36 ) have a leading edge ( 81 ) and a trailing edge ( 82 ), which are interconnected by outer edges ( 84 ) formed at the vane end ( 37 ), and the leading edge ( 81 ) and the trailing edge ( 82 ) extend in a manner directed radially outwardly and inclined upstream, wherein a vane face of the vane ( 36 ) is three-dimensionally twisted and the vane ( 36 ) is inclined in the direction of rotation relative to the meridian line, such that the leading edge ( 81 ) is oriented ahead of the trailing edge ( 82 ), and wherein an outer leading corner region ( 86 ) formed by the leading edge ( 81 ) and the outer edge ( 84 ) is inclined in an increased manner in the direction of rotation and/or a trailing corner region ( 88 ) formed between the trailing edge ( 82 ) and the outer edge ( 84 ) is inclined in an increased manner against the direction of rotation. (See FIG.  1 ).

This application claims priority of German Patent Application No. 102012 106 412.1 filed Jul. 17, 2012, which is hereby fully incorporatedherein by reference.

The invention relates to a diagonal impeller for a diagonal fan, and toa diagonal fan for gaseous media.

A diagonal impeller for a diagonal fan is known from DE 10 2010 032 168A1. Such fans can convey a flow medium consisting of air or other gasesfrom inside to outside. Fans of this type can be used for example at thestart, within, or at the end of pipelines, wherein the use is notlimited to the use of pipeline systems. A guide device for increasingthe pressure of the flow medium is provided downstream of the diagonalimpeller in the diagonal fan. The diagonal impeller consists of acarrier plate with vanes arranged thereon, which extend radiallyoutwardly in the direction of a cover plate. The cover plate is fastenedto an inlet nozzle, which is in turn arranged on an outer housingportion on an intake unit. The diagonal impeller is driven by a motor,wherein the motor shaft of said motor carries the carrier plate. Thevanes of the diagonal impeller and/or the guide vane of the guide deviceare three-dimensionally twisted. Improved efficacy compared totwo-dimensionally twisted vanes on a carrier plate, as are known forexample from U.S. Pat. No. 3,059,833, can thus be achieved. Due toincreasingly stricter guidelines on energy conservation, it is necessaryto further develop diagonal impellers of this type for diagonal fans, aswell as diagonal fans.

The object of the invention is to create a diagonal impeller and adiagonal fan comprising such a diagonal impeller, with which anincreased energy saving is made possible.

This object is achieved both by the independent claim relating to thediagonal impeller and by the independent claim relating to the diagonalfan. Further advantageous embodiments and developments are disclosed inthe other claims.

With the diagonal impeller according to the invention a leading cornerregion, formed by a leading edge and an outer edge, of the vane isinclined in an increased manner in the direction of rotation relative tothe adjoining vane face. Furthermore, an outer trailing corner regionformed between the trailing edge and the outer edge may alternatively beinclined in an increased manner against the direction of inflow. Acurved leading corner region and trailing corner region may also beprovided on a vane. Due to this increased curvature of the outer leadingcorner region in the direction of rotation and/or of the outer trailingcorner region against the direction of rotation, an increased build-upof pressure can be obtained with constant driving power of the motor andflow losses can be minimised, such that an optimised airflow is formed.An increase in efficiency can thus be achieved.

In accordance with a preferred embodiment of the vane geometry, theouter leading corner region is inclined over a region of less than aquarter of the length of the leading edge and the length of the outeredge. Only the outermost corner region is thus inclined or curved moregreatly in the direction of rotation, wherein the inclination over theouter edge and the leading edge is identical.

In accordance with a further preferred embodiment of the invention, theouter trailing corner region is inclined over a region of less than aquarter of the outer trailing edge. The same advantages as with theleading corner region are therefore obtained.

The curvature of the leading and/or trailing region is preferablyprovided in such a way that the leading edge or trailing edge, as viewedin the direction of rotation, is aligned in the respective corner regionso as to be practically horizontal or horizontal—that is to say in aplane perpendicular to the axis of rotation.

In accordance with a further preferred embodiment of the vane geometry,the free outer edge extends from the leading edge to the trailing edgein a flat, sinusoidal manner. The flow can thus be guided effectively.

In accordance with a further preferred embodiment of the diagonalimpeller, a corner region adjoining the trailing edge and a lateralsurface of the carrier plate is curved at said trailing edge in adirection opposite that of the outer trailing corner region. Thisarrangement enables an increased lifting effect of the flow, whereby anincrease in efficiency is in turn achieved.

The object of the invention is also achieved by a diagonal fan, whichcomprises a diagonal impeller, which comprises a guide device, attachedthereto in a downstream direction, to increase the pressure of the flowmedium and is surrounded, at least over portions, by a cover plate inthe radial direction as well as in the axial direction, an outer leadingcorner region formed by the leading edge and outer edge being inclinedin an increased manner in the direction of rotation and/or an outertrailing corner region formed between the trailing edge and the outerside being inclined in an increased manner against the direction ofrotation. Such a diagonal fan enables a further energy saving. Due tosuch a diagonal impeller in a diagonal fan, the different flow rates anddirections of inflow both at the inlet and at the outlet of the vanescan be optimally adapted so as to optimise the fluidic guidance of theair and to increase efficiency.

The invention and further advantageous embodiments and developmentsthereof will be described and explained in greater detail hereinafter onthe basis of the examples illustrated in the drawings. The features tobe derived from the description and the drawings can be applied inaccordance with the invention either individually or together in anycombination. In the drawings:

FIG. 1 shows a schematic sectional illustration of a diagonal fan,

FIG. 2 shows a perspective view of the diagonal impeller according tothe invention,

FIG. 3 shows a further perspective view of the diagonal impeller in FIG.2,

FIG. 4 shows a first side view of the diagonal impeller according toFIG. 2, and

FIG. 5 shows a further side view of the diagonal impeller according toFIG. 2 in a rotated position compared to FIG. 3.

A schematic sectional illustration of a diagonal fan 11 is illustratedin FIG. 1, said fan comprising an outer housing portion 12, inparticular a housing casing, which surrounds a circular cylindricalstraight cylinder interior. At the left-hand and right-hand end wall 14,15 of said housing portion, a right-hand and left-hand flange 17, 18respectively are fixedly attached externally to the housing portion 12.By means of these flanges 17, 18, a respective pipeline 21, 22(illustrated schematically) can be connected to either end of thehousing portion 12 and therefore to the diagonal fan 11. The diagonalfan 11 can thus be installed between these pipelines 21, 22. An outerdiameter of the pipelines 21, 22 may also correspond to the outerdiameter of the housing portion 12. The pipelines 21, 22 may also eachhave a diameter deviating from the diameter of the housing portion 12,and may be connected via a corresponding pipe adapter to the diagonalfan 11.

The diagonal fan 11 has a diagonal impeller 26, which is assigned on theinflow side to an intake unit 29. On the outflow side of the diagonalimpeller 26, a guide device 28 followed by a diffuser 30 are formedinside the diagonal fan 11. The diffuser 30 is formed by a blow-out unit31. The gaseous flow medium pushed through the diagonal fan 11 by meansof the diagonal impeller 26 circulates around a central interior of thediagonal fan 11, which is defined inwardly by a carrier plate 33 of thediagonal impeller 26 and an intermediate casing 34 adjoining the carrierplate 33 aerodynamically. The carrier plate 33 curves on the outflowside in an axial direction, so that it contacts the intermediate casing34, oriented in the axial direction, aerodynamically. The flow mediumtherefore flows radially outwardly past the carrier plate 33 and theintermediate casing 34.

The diagonal impeller 26 has peripherally distributed vanes 36, whichare fastened on one side to the carrier plate 33. On the opposite side,free vane ends 37 of the vanes 36 point toward a peripheral face 39 of acover plate 40, which is fastened to the housing portion 12. A gap 43 isformed therebetween between the vane ends 37 of the vanes 36 and theperipheral surface 35 of the cover plate 40. The vanes 34 are profiledcross-sectionally for example and are three-dimensionally twisted. Thecover plate 40 may form part of an inlet nozzle 41. Alternatively, theinlet nozzle 41 can be fastened to the housing portion 12 and may engagearound or carry the cover plate 40, so that an aerodynamic transitionbetween the intake unit 29 and guide device 28 is provided. If the inletnozzle 41 and cover plate 40 are each formed separately, an intermediateannular gap is produced, which can be sealed by a seal element.Alternatively, such an annular gap may also be formed as a flowlabyrinth.

The flow leaving the diagonal impeller 26 then flows through the regionof the guide device 28. In this portion of the diagonal fan 11,peripherally distributed stationary guide vanes 45 are arranged betweenthe intermediate casing 34 and the housing portion 12. The flow leavingin a helical, diagonal direction of the diagonal impeller 26 isdeflected in an axial direction of flow by the guide vanes 45. Similarlyto the vanes 36 of the diagonal impeller 26, the guide vanes 45 in thepresent example are also profiled and three-dimensionally twisted.Alternatively, the profiling of the vanes 36 and/or the guide vanes 45could also be omitted.

A motor 50, which drives the diagonal impeller 26 by means of adriveshaft 51, is located in the interior space 47 formed by the carrierplate 33 of the diagonal impeller 26 or by the intermediate casing 34 ofthe guide device 28. The motor 50 is flange-mounted on a motor holder,which extends from the intermediate casing 34 into the interior space47.

After the guide device 28, the diffuser 30 is formed downstream thereof.The diffuser 30 is constructed by an annular flow duct, that increasesin a downstream direction, between a motor cover 54 and a housing wall56 of the blow-out unit 31. The motor cover 54 is fastened to theintermediate casing 34 of the guide device 28 by means of a plurality ofscrews (not illustrated here) and closes the interior space 47 on theoutflow side.

The carrier plate 33 of the diagonal impeller 26 is fastened to themotor 50, in particular to the driveshaft 51, via a fastening element61. In this embodiment a gap 43 is set between the free vane ends 37 ofthe diagonal impeller 26 and the peripheral surface 39 of the coverplate 40.

The diagonal impeller 26 is illustrated in perspective view in FIG. 2.The carrier plate 33 consists of a rotationally symmetrical main body60, which, upstream, has a head region 63 with an end face 64. Forexample, an opening 65 is provided within the end face 64 so as tointroduce a fastening element of the fastening device 61 and so as toexchangeably fix the carrier plate 33 to the motor or the driveshaft 51thereof. The head region 63 transitions in a flowing manner into alateral surface 67, which ends in a foot region 68.

FIG. 3 shows a perspective view from beneath or behind the diagonalimpeller 26. Two schematic side views with different rotary positions ofthe diagonal impeller 26 are also illustrated in FIGS. 3 and 4.

The vanes 36 have a leading edge 81 (upstream), which is inclinedradially outwardly and upstream relative to the axis of rotation 62. Inaddition, this leading edge 81 is inclined extending in a straight lineand slightly in the direction of rotation. On the opposite side, thevane 36 has a trailing edge 82, which is likewise inclined upstream andextending in a straight line. The vane end 37 is formed between theleading edge 81 and the trailing edge 82 by an outer edge 84, whichsimultaneously forms a gap 43 between a cover plate 14, associated withthe diagonal impeller 26, and the peripheral surface 39 thereof.

In the region of transition between the leading edge 81 and the outeredge 84, an outer leading corner region 86 is formed, which has anincreased curvature in the direction of rotation so that it isapproximately horizontal, as viewed in the direction of rotation. Anouter trailing corner region 88 is formed oppositely between the outeredge 84 and the trailing edge 82 and is curved against the direction ofrotation. The trailing corner region 88 is thus curved in a directionopposite that of the leading corner region 86. An outer edge 84, whichextends in a flat, sinusoidal manner, is thus produced. The vane areasbetween the leading edge 81 and the trailing edge 82 as well as betweenthe outer edge 84 and a lateral surface 67 of the carrier plate 33 arethree-dimensionally twisted, that is to say they are not developable,wherein the flow rate and the separation behaviour are to be taken intoaccount in a region in the vicinity of the lateral surface and in aradially outer region in the vicinity of the vane ends 37.

The leading corner region 86 and the trailing corner region 88 have atype of spoiler function so as to obtain improved guidance of air intothe outer end regions.

In addition, in contrast to a frustum-shaped main body 60, the carrierplate preferably has a bell shape. In this case, at least one S-shapedundulation 70 is preferably provided between a head region 63 and a footregion 68, which are connected by the lateral surface 67, the bell shapebeing formed with the formation of an S-shaped undulation. Increasedcontouring of the adjoining vane face of the vane 36 can thus beenabled, in particular in a central region of the lateral surface.

The flow can be optimised as a result of the fact that the outer leadingcorner regions 86 and trailing corner regions 88 of the vanes 36 areeach curved in an increased manner.

1. Diagonal impeller for a diagonal fan, comprising a carrier plate overthe outer periphery of which a plurality of vanes are distributed, thevanes having a leading edge and a trailing edge, which areinterconnected by outer edges formed at the vane end, and the leadingedge and the trailing edge extending in a manner directed radiallyoutwardly and inclined upstream, a vane face of the vane beingthree-dimensionally twisted and the vane being inclined in the directionof rotation relative to the meridian line, such that the leading edge isoriented ahead of the trailing edge, wherein an outer leading cornerregion formed by the leading edge and the outer edge is inclined in anincreased manner in the direction of rotation and/or a trailing cornerregion formed between the trailing edge and the outer edge is inclinedin an increased manner against the direction of rotation or an outerleading corner region formed by the leading edge and the outer edge isinclined in an increased manner in the direction of rotation and atrailing corner region formed between the trailing edge and the outeredge is inclined in an increased manner against the direction ofrotation.
 2. Diagonal impeller according to claim 1, wherein the outerleading corner region is inclined over a region of less than a quarterof the length of the leading edge and the length of the outer edge. 3.Diagonal impeller according to claim 1, wherein the outer trailingcorner region is inclined over a region of less than a quarter of thelength of the trailing edge and the length of the outer edge. 4.Diagonal impeller according to claim 1, wherein the outer edge extendsin a flat, sinusoidal manner starting from the leading edge as far asthe trailing edge.
 5. Diagonal impeller according to claim 1, whereinthe leading edge in the leading corner region and/or the trailing edgein the trailing corner region are aligned, at least over portions, in aplane practically perpendicular or in a plane perpendicular to the axisof rotation of the carrier plate.
 6. Diagonal impeller according toclaim 1, wherein a corner region adjoining the trailing edge andarranged on a lateral surface of the carrier plate is curved in adirection opposite that of the outer trailing corner region.
 7. Diagonalfan for gaseous media, comprising a diagonal impeller, which has acarrier plate with a plurality of vanes arranged thereon, with a guidedevice following said diagonal impeller in a downstream direction toincrease the pressure of the flow medium and with a cover plate, whichsurrounds the carrier plate in the radial direction and extends alongthe carrier plate, at least over portions, in the axial direction,wherein the diagonal impeller is designed according to claim 1.